“The Net thrower”. The fisherman are conducting activities on Situgunung Lake. Photo location: Situgunung lake, Sukabumi, West Java, Indonesia. (Photo and caption by Dody Kusuma/National Geographic Photo Contest)

Relatives of victims react as a rescue worker asks them to leave an area hit by landslides in Sumedang regency, West Java province, Indonesia on January 11, 2021. (Photo by Raisan Al Farisi/Antara Foto via Reuters)

A resident pushes their motorbike through flood waters caused by torrential rain in Semarang, central Java, Indonesia on February 23, 2021. (Photo by W.F. Sihardian/NurPhoto/Rex Features/Shutterstock)

Indonesian soldiers wearing facemasks and personal protective equipment take a part in a sack race during games to celebrate ahead of the country's 75th Independence Day in Surabaya, East Java on August 14, 2020. Indonesia will mark its 75th Independence Day on August 17. (Photo by Juni Kriswanto/AFP Photo)

Located in East Java, Indonesia, Kawah Ijen is a volcano is home to the largest acidic crater lake in the world. What turns the waters of the lake in the 1 km caldera its beautiful turquoise color are the highly sulfuric gases emitted from the volcano underneath.

Indonesian tourists take a selfie as Mount Bromo spews volcanic material and ash into the air during an eruption in Probolinggo, East Java, Indonesia, 31 December 2015. Indonesia's Mount Bromo is on the second highest alert level as its activity has increased in the last two months. (Photo by Fully Handoko/EPA)

In this photograph taken on June 11, 2018, Chinese artists performs during a Indo-China cultural exchange program in Kolkata, West Bengal, India. (Photo by Dibyangshu Sarkar/AFP Photo)

Indonesian activists covered with sludge from the mud volcano hold a protest during five year anniversary of the Sidoarjo mud eruption on May 29, 2011 in the subdistrict of Porong in Sidoarjo, East Java, Indonesia. (Photo by Ulet Ifansasti/Getty Images)